Umair Muhammad, Jabbar Saqib, Sultana Tayyaba, Ayub Zubaria, Abdelgader Sheikheldin A, Xiaoyu Zhu, Chong Zhang, Fengxia Lu, Xiaomei Bie, Zhaoxin Lu
College of Food Science and Technology Nanjing Agriculture University Nanjing China.
Food Science Research Institute (FSRI) National Agricultural Research Centre (NARC) Islamabad Pakistan.
Food Sci Nutr. 2020 Jul 28;8(9):4843-4856. doi: 10.1002/fsn3.1766. eCollection 2020 Sep.
The present study explores the effect of chirality of the biological macromolecules, its functional aspects, and its interaction with other food components. Dihydromyricetin (DHM) is a natural novel flavonol isolated from the vine tea ( leaves. However, limited progress in enantiopure separation methods of such compounds hinder in the development of enantiopure functional studies. This study is an attempt to develop a simple, accurate, and sensitive extraction method for the separation of the enantiopure DHM from vine tea leaves. In addition, the identification and purity of the extracted enantiopure (-)-DHM were further determined by the proton nuclear magnetic resonance (H-NMR) and the carbon nuclear magnetic resonance (C-NMR). The study further evaluates the antimicrobial activity of isolated (-)-DHM in comparison with racemate (+)-DHM, against selected foodborne pathogens, whereas the action mode of enantiopure (-)-DHM to increase the integrity and permeability of the bacterial cell membrane was visualized by confocal laser scanning microscopy using green fluorescence nucleic acid dye (SYTO-9) and propidium iodide (PI). Moreover, the morphological changes in the bacterial cell structure were observed through field emission scanning electron microscope. During analyzing the cell morphology of (AS11846), it was confirmed that enantiopure (-)-DHM could increase the cell permeability that leads to the released of internal cell constituents and, thus, causes cell death. Therefore, the present study provides an insight into the advancement of enantiopure isolation along with its antimicrobial effect which could be served as an effective approach of biosafety.
本研究探讨了生物大分子的手性效应、其功能方面以及它与其他食品成分的相互作用。二氢杨梅素（DHM）是从藤茶（叶）中分离出的一种天然新型黄酮醇。然而，此类化合物对映体纯分离方法的进展有限，阻碍了对映体纯功能研究的发展。本研究旨在开发一种简单、准确且灵敏的提取方法，用于从藤茶叶中分离对映体纯的DHM。此外，通过质子核磁共振（H-NMR）和碳核磁共振（C-NMR）进一步确定了提取的对映体纯（-）-DHM的鉴定和纯度。该研究进一步评估了分离出的（-）-DHM与外消旋体（+）-DHM相比，对选定食源性病原体的抗菌活性，而使用绿色荧光核酸染料（SYTO-9）和碘化丙啶（PI）的共聚焦激光扫描显微镜观察了对映体纯（-）-DHM增加细菌细胞膜完整性和通透性的作用模式。此外，通过场发射扫描电子显微镜观察了细菌细胞结构的形态变化。在分析（AS11846）的细胞形态时，证实对映体纯（-）-DHM可增加细胞通透性，导致细胞内成分释放，从而导致细胞死亡。因此，本研究深入了解了对映体纯分离及其抗菌作用的进展，这可作为一种有效的生物安全方法。
